BIND 9.3.2 on FreeBSD 6.1 out of control

[Gushi]

I'll try this once BIND 9.4 settles into ports.  Jinmei, thanks for all
the advice.

-Dan

JINMEI Tatuya / 神明達哉 wrote:
> >>>>> On Mon, 15 Jan 2007 16:17:27 -0600,
> >>>>> "Matthew Schlosser" <mschlosser at eschelon.com> said:
>
> >> I've often heard this type of symptom, especially on FreeBSD.  One
> >> common cause is that BIND9's cache cleaning (prior to 9.4) relies on
> >> system's malloc()/free() routines, which could run inefficiently on
> >> FreeBSD (I'm not really sure if it's still the case for 6.1, but it
> >> was at least for some 4.X versions); and one common workaround is to
> >> enable BIND9's internal memory allocator by rebuilding BIND9 with:
> >>
> >> % ./configure STD_CDEFINES='-DISC_MEM_USE_INTERNAL_MALLOC=1'
> >>
> >> This should be very effectively particularly for the case of cache
> >> cleaning because it will most likely recycle pre-allocated memory
> >> fragments without involving any system calls or possible-inefficient
> >> standard libraries.
>
> > Could this affect the problem I'm having (see message "Bind9 Crazy-high CPU
> > on Linux")?  The symptoms are similar, but not the same.
>
> Perhaps, but it also depends on details of the problem and of your
> environment, especially the memory usage when the problem occurs and
> whether you specify max-cache-size (and if yes the value of the
> option).
>
> It should also be noted that even if the use of the internal allocator
> mitigates the problem it doesn't change the fact that cache cleaning
> is a heavy task.  So, while cleaning the cache, the CPU will still be
> pretty busy (the busy period will probably be shortened), and some
> incoming queries may still be dropped during the period.  BIND 9.4
> remedies the query drop issue further, by adjusting non-interruptible
> cleaning periods (during which queries aren't processed) based on
> average query rate.
>
> In summary,
>
> - the internal allocator on 9.3 may help, but the CPU will still be
>   busy (though the busy period may be shorter) and queries may still
>   be dropped during the busy period.
> - 9.4 may also help, and hopefully there will be no query drops;
>   however, the CPU will still be busy for some shorter period.
>
> 					JINMEI, Tatuya
> 					Communication Platform Lab.
> 					Corporate R&D Center, Toshiba Corp.
> 					jinmei at isl.rdc.toshiba.co.jp